“…To a lesser extent, the compounds with negative photochromism [10]-norbornadienes [11,12], acylotropic enaminoketones [13], and azomethine imines [14]-are described. Azomethine imine molecules possess a polar 1,3-dipole N − -N + =C fragment, which makes these compounds to be valuable precursors in the combinatorial chemistry of heterocycles prepared by cycloaddition reactions [15][16][17][18][19][20][21]. The resulting products containing a pyrazolidine cycle annulated to other heterocycles find application in medicine as the multipurpose biologically active compounds [22], anti-HIV agents, inhibitors of NO synthase, and antidiabetic drugs [23][24][25][26], in agriculture [27,28], and in other fields of science and technology [29].…”